The RTOG Statistics Department was established to collaborate with RTOG investigators in defining the optimum management of cancer patients, particularly when this care includes radiation therapy, either alone or in combination with other modalities. These efforts should lead to extended survival, improved tumor control, enhanced quality of life, and an ultimate cure. To achieve this objective, the Statistical Unit collaborates with RTOG investigators in conducting multicenter randomized and nonrandomized clinical trials to evaluate the safety and efficacy of novel therapies, in the treatment of patients with cancer. The RTOG statisticians work with the RTOG investigators to develop and implement research strategies in a series of well-designed trials. They assure that the role of each new treatment regimen receives adequate phase I/II evaluation. The results can then be incorporated into designing subsequent phase III trials with minimal delay, a minimum but sufficient number of patients, and a maximum chance of detecting clinically significant differences. The RTOG statisticians further collaborate with RTOG investigators in carefully monitoring ongoing trials, performing timely and appropriate analyses, and promptly reporting the results. The RTOG Statistics Department determines randomization schemes and develops systems for processing and analyzing the clinical databases. RTOG also conducts studies in correlating laboratory findings and outcomes research [Quality of Life (QOL), Special Populations (SP), Economic Impact (EI), and Epidemiology Subcommittees (EP)] endpoints with treatment outcome. The laboratory studies may lead to a better understanding of the fundamental nature of the malignant process and predict the responsiveness of tumors to various therapies. The RTOG evaluates every study for potential inclusion of outcome research endpoints. In studies where these endpoints are appropriate, the Statistics Department collaborates with the RTOG investigator on the design of case report forms to obtain the necessary data. Given these findings from the laboratory and the outcomes studies, treatments can be more logically planned for individual patients. The RTOG Statistics Department collaborates with RTOG investigators in the design, monitoring, and analysis of all these studies.